X0306 4 2020-02-10 0 0001399529 Dicerna Pharmaceuticals Inc DRNA 0001598479 Brown Bob D C/O DICERNA PHARMACEUTICALS, INC. 33 HAYDEN AVENUE LEXINGTON MA 02421 0 1 0 0 See Remarks Common Stock 2020-02-10 4 M 0 5650 3.42 A 10650 D Common Stock 2020-02-10 4 M 0 2535 3.42 A 13185 D Common Stock 2020-02-10 4 S 0 8185 21.00 D 5000 D Employee Stock Option (Right to Buy) 3.42 2020-02-10 4 M 0 5650 0.00 D 2023-09-24 Common Stock 5650 81850 D Employee Stock Option (Right to Buy) 3.42 2020-02-10 4 M 0 2535 0.00 D 2023-09-24 Common Stock 2535 99124 D The reporting person sold an aggregate of 8,185 shares of common stock on February 10, 2020 (the "Shares Sold") as reported in this Form 4. The Shares Sold represent 0.77% of 1,058,484 shares of common stock, which is the number of shares of common stock owned by the reporting person prior to the Shares Sold transaction reported in this Form 4, as well as shares issuable upon exercise or settlement of vested and unvested options and restricted stock units held by the reporting person as of the date of this report. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 27, 2019. The vesting of this option was subject to achievement of pre-established performance goals. As of the transaction date, the option was fully vested. The option vested 1/48 monthly on last day of each month with the vesting start date of 7/30/2013. EVP of R&D, Chief Scientific Officer /s/ John B. Green, attorney-in-fact 2020-02-10